摘要
计算了 1 998年 6～ 7月和 2 0 0 1年 6～ 7月 50 0hPa高度场西太平洋副热带高压逐日变化指数 ,对比分析了 1 998年和 2 0 0 1年长江流域梅汛期 ( 6～ 7月 )平均北半球大气环流场和西太平洋副高的逐日变化特征。结果表明 :长江流域梅汛期的旱涝与副高强弱和东西位置关系密切。在副高平均脊线偏北的情况下 ,副高长期偏东偏弱 ,长江流域不易产生强降水 ,易少雨干旱。副高异常偏西与伊朗高压打通时 ,长江流域也不易产生强降水。只有当副高平均脊线偏南的情况下 ,副高西伸到 95～ 1 1 5°E范围时 ,长江流域易产生强降水。
The day-to-day change indexes of the western Pacific subtropical high (STH) at 500hPa from June to July of 1998 and 2001 over the Changjiang River valley are calculated. The atmospheric circulation field of the northern Hemisphere and the daily variation features of STH in the Changjiang River valley during plum rains season are comparatively analyzed. The result shows that the flood/drought in the Changjiang River valley during plum rains season is closely related with the STH intensity and east/ west location. It is also found that the strong precipitation in the Changjiang River valley uneasily occurs not only when STH is weak and its location is eastward of the mean for a long time, but also it connects with Iran high and anomaly westward of the mean. But the strong precipitation in the Changjiang River valley easily occurs when STH′s mean ridge line is located by the south and its west-end in 95～115°E.
出处
《气象》
CSCD
北大核心
2003年第6期7-11,共5页
Meteorological Monthly
基金
973国家重点应用基础研究项目 (G19980 4 0 90 8)资助。
